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From:   Stephen Boyd <swboyd@chromium.org>
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Date:   Thu, 26 May 2022 16:03:02 -0400
Message-ID: <CAE-0n53SJkTLGg60BURV_3c3C_cB4JyAQx-TUe4mRXyT42G4Fg@mail.gmail.com>
Subject: Re: [PATCH] leds: qcom-lpg: Require pattern to follow documentation
To:     Bjorn Andersson <bjorn.andersson@linaro.org>,
        Jonathan Corbet <corbet@lwn.net>,
        Marijn Suijten <marijn.suijten@somainline.org>,
        Pavel Machek <pavel@ucw.cz>
Cc:     Matthias Kaehlcke <mka@chromium.org>,
        Satya Priya <quic_c_skakit@quicinc.com>,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-leds@vger.kernel.org, linux-arm-msm@vger.kernel.org
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Quoting Bjorn Andersson (2022-05-23 16:37:19)
> The leds-trigger-pattern documentation describes how the brightness of
> the LED should transition linearly from one brightness value to the
> next, over the given delta_t.
>
> But the pattern engine in the Qualcomm LPG hardware only supports
> holding the brightness for each entry for the period.
> This subset of patterns can be represented in the leds-trigger-pattern
> by injecting zero-time transitions after each entry in the pattern,
> resulting in a pattern that pattern that can be rendered by the LPG.

s/that pattern//

>
> Rework LPG pattern interface to require these zero-time transitions, to
> make it comply with this subset of patterns and reject the patterns it
> can't render.
>
> Fixes: 24e2d05d1b68 ("leds: Add driver for Qualcomm LPG")
> Signed-off-by: Bjorn Andersson <bjorn.andersson@linaro.org>
> ---

Reviewed-by: Stephen Boyd <swboyd@chromium.org>